Image of the Janis-Newman-Winicour naked singularity with a thin accretion disk
Abstract
We study the optical appearance and the apparent radiation flux of a geometrically thin and optically thick accretion disk around the static Janis-Newman-Winicour naked singularity. We confine ourselves to the astrophysically most relevant case, when the solution possesses a photon sphere, assuming that the radiation emitted by the disk is described by the Novikov-Thorne model. The observable images closely resemble the visual appearance of the Schwarzschild black hole, as only quantitative differences are present. For the Janis-Newman-Winicour solution the accretion disk appears smaller, and its emission is characterized by a higher peak of the radiation flux. In addition, the most significant part of the radiation is concentrated in a closer neighborhood of the flux maximum. The results are obtained independently by two alternative methods, consisting of a semianalytical scheme using the spherical symmetry of the spacetime, and a fully numerical ray-tracing procedure valid for any stationary and axisymmetric spacetime.
- Publication:
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Physical Review D
- Pub Date:
- July 2019
- DOI:
- 10.1103/PhysRevD.100.024055
- arXiv:
- arXiv:1905.05273
- Bibcode:
- 2019PhRvD.100b4055G
- Keywords:
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- General Relativity and Quantum Cosmology;
- Astrophysics - High Energy Astrophysical Phenomena
- E-Print:
- 21 pages